High-purity pentane differential pressure thermal coupling energy-saving technology

The invention relates to a differential pressure thermal coupling energy-saving technology for preparing high-purity pentane. In tihe technology, the operating pressure of one of the heavy component eliminating tower and the pentane separation tower is increased appropriately to obtain a pressure column and the operating pressure of the other tower is decreased appropriately to obtain a vaccum tower, thus the temperature difference between the overhead condensate of the pressure column and the temperature of the reboiled gas phase in the kettle of the vaccum tower is more than a minimum heat transfer temperature difference; the heat released by the overhead steam of the pressure column is used to heat the liquid phase in the kettle of the vaccum tower, the matching of the heat of the two materials is utilized to realize the thermal coupling of the two towers; and an auxiliary heat exchanger is used to completely match the energy consumption of the entire rectification process, thus realizing the energy-saving aim. A siding is added on the upper-middle part of the pentane separation tower, thus partial mixture of pentane is withdrawn to be used as the foaming agent. The invention has the following advantages: compared with the method that the pentane mixed foaming agent is prepared by blending pure n-pentane and isopentane, a larger amount of energy can be saved; and the operating flexibility is higher.